1. Field of the Invention
The present disclosure relates to an image forming apparatus such as a copier, a printer, or a fax device that uses an electrophotographic method or an electrostatic recording method.
2. Description of the Related Art
An image forming apparatus performs printing by, for example, forming toner images on an image carrier such as a photosensitive member or an intermediate transfer belt and ultimately transferring these toner images to a recording material that is also an image carrier. Note that in order to remove remaining toner that has not been transferred from an image carrier to another image carrier, or in other words, transfer remnant toner, a rubber cleaning blade is used as a cleaning unit in the image forming apparatus. Here, transfer remnant toner also acts as a lubricant and suppresses the frictional force between the cleaning blade and the image carrier. In other words, the transfer remnant toner suppresses curling-up of the tip of the cleaning blade caused by excessive friction between the cleaning blade and the image carrier, and the like, and prevents cleaning defects from occurring.
However, if the amount of transfer remnant toner is not sufficient, it is not possible to sufficiently reduce friction. Because of this, Japanese Patent Laid-Open No. 2009-205109 discloses that if the area of a formed image is small, toner is mandatorily supplied to the image carrier in order to reduce the frictional force between the cleaning blade and the image carrier.
For example, if printing is performed successively on multiple recording materials and many of the images to be printed on the recording materials have a large area, an amount of transfer remnant toner that is sufficient to suppress the frictional force exists in the vicinity of the cleaning blade. Accordingly, in such a case, toner does not need to be mandatorily supplied to the image carrier even if the areas of the images that are to be printed on some recording materials are small. Similarly, even in the case of printing images having small areas, if images having large areas have been printed prior to the printing of images having small areas, the amount of transfer remnant toner is sufficient to suppress the frictional force and it is not necessary to mandatorily supply toner. However, with the method disclosed in Japanese Patent Laid-Open No. 2009-205109, there is a possibility that toner will be mandatorily supplied, even in such cases. In this way, with the method disclosed in Japanese Patent Laid-Open No. 2009-205109, more toner than is necessary is supplied, and toner, or in other words, developing material is needlessly consumed.